Im having a hard time getting Duratec on the vertical surfaces of a mold with enough thickness to prevent alligatoring.
What do you think? Mix 50/50 Duratec/clear gelcoat, or is there a way to prevent it with a thin gelcoat layer?
Using VER.
just do more light passes and slowly build up your thickness, too thick will cause the aligating. you dont need any more then 20 mils. you also need to make sure you use the correct ratio of catalyst, about 2 percent
I was thinking opposite, I have something else going wrong then.
Your mold is complete and now you want to spray Duratec clear onto the surface of the mold, so the part will have a clear surface finish? Or you are spraying Duratec primer to finish off a mold?
I believe he is spraying the mold with either duratec clear or a primer for a part he will be making but it is alligating on the vertical areas. im thinking hes laying it down to thick, but who knows
Alligatoring is from too thin gel coating…
Read this booklet: http://www.compositeforum.werksberg.com/showthread.php?t=2043
yes, but I believe this is happening before he starts laying up.
fz1… are you brushing or spraying the gel coat?
I would think if the OP is trying to brush a product intended for spray application, thats almost certainly going to be causing uneven coverage, with some thin areas that will be prone to problems with alligatoring.
I’m using the Duratec clear as a gel coat for making the part, sprayed.
I figured out what went wrong (I think).
I’m using a stretch bagging film, under full vacuum the bagging film is tight in all the corners edges ect.
When I take the clamp off the resin (infusion) and it starts to flow this raises the pressure inside the bagging film allowing it to unstretch and separate from the mold and fabric ect. The areas pooled with resin to fill the gap, and that is where the alligatoring was.
I infused on last night and did a better job on the bagging film, and not counting on the stretch to get in the corners and it turned out fine.
Thanks for the link
Duratec also has very detailed info regarding applying thier various products, which may be helpful.
Glad to hear i’m not the only one with infusion problem… i had a major air leak on one today, that and i forgot to clamp off the resin line so when i turned on the vacuum almost all the resin got imediatly sucked into the lay up. What a disaster on a small scale. I never could get the air leak plugged or stopped up. stupid freaking thing. I’m gonna have to buy some yellow sticky tape just for the resin lines. I saw a trick little connector for the vacuum side, you cut a small opening into the bag and the connector screws down onto the bag sealing via o-ring. That would solve the leaks at the vacuum side at least. Nope, the bag is just fine, no holes in it. lol
I also am not going to infuse anymore without a resin pot… Harbor Freight here i come.
you should be mixing you resin after you have fully vacuumed bag your part and have taken care of any leaks and bridges.
yeah, i got in a hurry i guess or was kinda winging it without the resin pot. I’ll buy one this week. I’ll also wait like you suggested about pulling full vacuum and checking for leaks before mixing the resin. thanks
yea, and you should get a quick disconnect for your catch pot, so once you think you have no leaks, disconnect the vacuum, your bag should hold bag pressure for atleast 10-15 minutes if you have no leaks. if you have a leak you will loose your pressure within minutes. also think about investing in a ultrasonic tester to help finding leaks, worth every cent
I have a cheap inficon ultrasonic leak detector (don’t know the model off hand). It’s not too effective in my opinion, maybe I don’t have the right technique yet. What do you have hojo?
I knew someone would say this, and when I first started I thought the same thing. I didnt use it for years. but now I cant live without it. there are so many leaks you cant hear with the human ear, that is why you need a ultrasonic teser. make sure you wear the headphones, dont just look at the led’s, they dont help much. I forget the brand tester I use, but you can adjust the sensitivity up to 12, I always use it at 11 first, then at the end go over the bag again with 12
Maybe I made up my mind too fast. After about half an hour of testing I felt thoroughly dissapointed. It’s an Inficon Whisper.